1. Field of the Invention
The invention relates to an apparatus for cooling a piston of an internal combustion engine and, specifically, to an apparatus for cooling a piston by injecting oil from the back surface of the piston.
2. Description of the Related Art
Conventionally, as an apparatus for cooling a piston of an internal combustion engine, there is known an apparatus structured such that a nozzle pipe for forming a cooling oil flow passage in communication with an oil path formed within the internal combustion engine is extended toward the back surface of the piston and oil is injected from this nozzle pipe.
This conventional technology, for example, JP-UM-A-S54-164328 provides an integrated structure that a filter is provided within an oil chamber in the main body of a cooling apparatus removably mounted on an internal combustion engine and a nozzle pipe is disposed downstream of the filter. Thus, the filter within the main body is used to prevent the nozzle pipe from being clogged. Since, in the integrated type cooling apparatus with the built-in filter, simultaneously when the cooling apparatus is assembled, the filter is assembled, the assembling efficiency is high.
However, in the structure disclosed in JP-UM-A-S54-164328, since the filter is built within the main body of the cooling apparatus, when maintaining the apparatus, for example, when cleaning and replacing the filter, the main body must be divided and disassembled. Therefore, the maintenance work is complicated. Also, not only the main body must have a structure capable of incorporating and supporting the filter but also, in order that the filter can be mounted onto and removed from the main body, the main body itself must be structured such that it can be divided and reassembled. Thus, the structure of the main body tends to be complicated, thereby raising a possibility that the cost and size of the cooling apparatus can be increased.
On the other hand, in the case that the filter is irremovably mounted on the main body of the cooling apparatus, the structure can be simplified. In this case, however, when maintaining the cooling apparatus, the whole of the cooling apparatus must be replaced, thereby causing the cost to increase.